2 * linux/kernel/ptrace.c
4 * (C) Copyright 1999 Linus Torvalds
6 * Common interfaces for "ptrace()" which we do not want
7 * to continually duplicate across every architecture.
10 #include <linux/capability.h>
11 #include <linux/export.h>
12 #include <linux/sched.h>
13 #include <linux/errno.h>
15 #include <linux/highmem.h>
16 #include <linux/pagemap.h>
17 #include <linux/ptrace.h>
18 #include <linux/security.h>
19 #include <linux/signal.h>
20 #include <linux/uio.h>
21 #include <linux/audit.h>
22 #include <linux/pid_namespace.h>
23 #include <linux/syscalls.h>
24 #include <linux/uaccess.h>
25 #include <linux/regset.h>
26 #include <linux/hw_breakpoint.h>
27 #include <linux/cn_proc.h>
28 #include <linux/compat.h>
32 * ptrace a task: make the debugger its new parent and
33 * move it to the ptrace list.
35 * Must be called with the tasklist lock write-held.
37 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
39 BUG_ON(!list_empty(&child->ptrace_entry));
40 list_add(&child->ptrace_entry, &new_parent->ptraced);
41 child->parent = new_parent;
45 * __ptrace_unlink - unlink ptracee and restore its execution state
46 * @child: ptracee to be unlinked
48 * Remove @child from the ptrace list, move it back to the original parent,
49 * and restore the execution state so that it conforms to the group stop
52 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
53 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
54 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
55 * If the ptracer is exiting, the ptracee can be in any state.
57 * After detach, the ptracee should be in a state which conforms to the
58 * group stop. If the group is stopped or in the process of stopping, the
59 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
60 * up from TASK_TRACED.
62 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
63 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
64 * to but in the opposite direction of what happens while attaching to a
65 * stopped task. However, in this direction, the intermediate RUNNING
66 * state is not hidden even from the current ptracer and if it immediately
67 * re-attaches and performs a WNOHANG wait(2), it may fail.
70 * write_lock_irq(tasklist_lock)
72 void __ptrace_unlink(struct task_struct *child)
74 BUG_ON(!child->ptrace);
77 child->parent = child->real_parent;
78 list_del_init(&child->ptrace_entry);
80 spin_lock(&child->sighand->siglock);
83 * Clear all pending traps and TRAPPING. TRAPPING should be
84 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
86 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
87 task_clear_jobctl_trapping(child);
90 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
93 if (!(child->flags & PF_EXITING) &&
94 (child->signal->flags & SIGNAL_STOP_STOPPED ||
95 child->signal->group_stop_count)) {
96 child->jobctl |= JOBCTL_STOP_PENDING;
99 * This is only possible if this thread was cloned by the
100 * traced task running in the stopped group, set the signal
101 * for the future reports.
102 * FIXME: we should change ptrace_init_task() to handle this
105 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
106 child->jobctl |= SIGSTOP;
110 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
111 * @child in the butt. Note that @resume should be used iff @child
112 * is in TASK_TRACED; otherwise, we might unduly disrupt
113 * TASK_KILLABLE sleeps.
115 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
116 ptrace_signal_wake_up(child, true);
118 spin_unlock(&child->sighand->siglock);
121 /* Ensure that nothing can wake it up, even SIGKILL */
122 static bool ptrace_freeze_traced(struct task_struct *task)
126 /* Lockless, nobody but us can set this flag */
127 if (task->jobctl & JOBCTL_LISTENING)
130 spin_lock_irq(&task->sighand->siglock);
131 if (task_is_traced(task) && !__fatal_signal_pending(task)) {
132 task->state = __TASK_TRACED;
135 spin_unlock_irq(&task->sighand->siglock);
140 static void ptrace_unfreeze_traced(struct task_struct *task)
142 if (task->state != __TASK_TRACED)
145 WARN_ON(!task->ptrace || task->parent != current);
147 spin_lock_irq(&task->sighand->siglock);
148 if (__fatal_signal_pending(task))
149 wake_up_state(task, __TASK_TRACED);
151 task->state = TASK_TRACED;
152 spin_unlock_irq(&task->sighand->siglock);
156 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
157 * @child: ptracee to check for
158 * @ignore_state: don't check whether @child is currently %TASK_TRACED
160 * Check whether @child is being ptraced by %current and ready for further
161 * ptrace operations. If @ignore_state is %false, @child also should be in
162 * %TASK_TRACED state and on return the child is guaranteed to be traced
163 * and not executing. If @ignore_state is %true, @child can be in any
167 * Grabs and releases tasklist_lock and @child->sighand->siglock.
170 * 0 on success, -ESRCH if %child is not ready.
172 static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
177 * We take the read lock around doing both checks to close a
178 * possible race where someone else was tracing our child and
179 * detached between these two checks. After this locked check,
180 * we are sure that this is our traced child and that can only
181 * be changed by us so it's not changing right after this.
183 read_lock(&tasklist_lock);
184 if (child->ptrace && child->parent == current) {
185 WARN_ON(child->state == __TASK_TRACED);
187 * child->sighand can't be NULL, release_task()
188 * does ptrace_unlink() before __exit_signal().
190 if (ignore_state || ptrace_freeze_traced(child))
193 read_unlock(&tasklist_lock);
195 if (!ret && !ignore_state) {
196 if (!wait_task_inactive(child, __TASK_TRACED)) {
198 * This can only happen if may_ptrace_stop() fails and
199 * ptrace_stop() changes ->state back to TASK_RUNNING,
200 * so we should not worry about leaking __TASK_TRACED.
202 WARN_ON(child->state == __TASK_TRACED);
210 static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
212 if (mode & PTRACE_MODE_NOAUDIT)
213 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
215 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
218 /* Returns 0 on success, -errno on denial. */
219 static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
221 const struct cred *cred = current_cred(), *tcred;
222 struct mm_struct *mm;
226 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
227 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
231 /* May we inspect the given task?
232 * This check is used both for attaching with ptrace
233 * and for allowing access to sensitive information in /proc.
235 * ptrace_attach denies several cases that /proc allows
236 * because setting up the necessary parent/child relationship
237 * or halting the specified task is impossible.
240 /* Don't let security modules deny introspection */
241 if (same_thread_group(task, current))
244 if (mode & PTRACE_MODE_FSCREDS) {
245 caller_uid = cred->fsuid;
246 caller_gid = cred->fsgid;
249 * Using the euid would make more sense here, but something
250 * in userland might rely on the old behavior, and this
251 * shouldn't be a security problem since
252 * PTRACE_MODE_REALCREDS implies that the caller explicitly
253 * used a syscall that requests access to another process
254 * (and not a filesystem syscall to procfs).
256 caller_uid = cred->uid;
257 caller_gid = cred->gid;
259 tcred = __task_cred(task);
260 if (uid_eq(caller_uid, tcred->euid) &&
261 uid_eq(caller_uid, tcred->suid) &&
262 uid_eq(caller_uid, tcred->uid) &&
263 gid_eq(caller_gid, tcred->egid) &&
264 gid_eq(caller_gid, tcred->sgid) &&
265 gid_eq(caller_gid, tcred->gid))
267 if (ptrace_has_cap(tcred->user_ns, mode))
275 ((get_dumpable(mm) != SUID_DUMP_USER) &&
276 !ptrace_has_cap(mm->user_ns, mode)))
279 return security_ptrace_access_check(task, mode);
282 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
286 err = __ptrace_may_access(task, mode);
291 static int ptrace_attach(struct task_struct *task, long request,
295 bool seize = (request == PTRACE_SEIZE);
302 if (flags & ~(unsigned long)PTRACE_O_MASK)
304 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
312 if (unlikely(task->flags & PF_KTHREAD))
314 if (same_thread_group(task, current))
318 * Protect exec's credential calculations against our interference;
319 * SUID, SGID and LSM creds get determined differently
322 retval = -ERESTARTNOINTR;
323 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
327 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
329 struct mm_struct *mm = task->mm;
330 if (mm && ns_capable(mm->user_ns, CAP_SYS_PTRACE))
331 flags |= PT_PTRACE_CAP;
337 write_lock_irq(&tasklist_lock);
339 if (unlikely(task->exit_state))
340 goto unlock_tasklist;
342 goto unlock_tasklist;
346 task->ptrace = flags;
348 __ptrace_link(task, current);
350 /* SEIZE doesn't trap tracee on attach */
352 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
354 spin_lock(&task->sighand->siglock);
357 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
358 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
359 * will be cleared if the child completes the transition or any
360 * event which clears the group stop states happens. We'll wait
361 * for the transition to complete before returning from this
364 * This hides STOPPED -> RUNNING -> TRACED transition from the
365 * attaching thread but a different thread in the same group can
366 * still observe the transient RUNNING state. IOW, if another
367 * thread's WNOHANG wait(2) on the stopped tracee races against
368 * ATTACH, the wait(2) may fail due to the transient RUNNING.
370 * The following task_is_stopped() test is safe as both transitions
371 * in and out of STOPPED are protected by siglock.
373 if (task_is_stopped(task) &&
374 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
375 signal_wake_up_state(task, __TASK_STOPPED);
377 spin_unlock(&task->sighand->siglock);
381 write_unlock_irq(&tasklist_lock);
383 mutex_unlock(&task->signal->cred_guard_mutex);
386 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT,
387 TASK_UNINTERRUPTIBLE);
388 proc_ptrace_connector(task, PTRACE_ATTACH);
395 * ptrace_traceme -- helper for PTRACE_TRACEME
397 * Performs checks and sets PT_PTRACED.
398 * Should be used by all ptrace implementations for PTRACE_TRACEME.
400 static int ptrace_traceme(void)
404 write_lock_irq(&tasklist_lock);
405 /* Are we already being traced? */
406 if (!current->ptrace) {
407 ret = security_ptrace_traceme(current->parent);
409 * Check PF_EXITING to ensure ->real_parent has not passed
410 * exit_ptrace(). Otherwise we don't report the error but
411 * pretend ->real_parent untraces us right after return.
413 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
414 current->ptrace = PT_PTRACED;
415 __ptrace_link(current, current->real_parent);
418 write_unlock_irq(&tasklist_lock);
424 * Called with irqs disabled, returns true if childs should reap themselves.
426 static int ignoring_children(struct sighand_struct *sigh)
429 spin_lock(&sigh->siglock);
430 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
431 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
432 spin_unlock(&sigh->siglock);
437 * Called with tasklist_lock held for writing.
438 * Unlink a traced task, and clean it up if it was a traced zombie.
439 * Return true if it needs to be reaped with release_task().
440 * (We can't call release_task() here because we already hold tasklist_lock.)
442 * If it's a zombie, our attachedness prevented normal parent notification
443 * or self-reaping. Do notification now if it would have happened earlier.
444 * If it should reap itself, return true.
446 * If it's our own child, there is no notification to do. But if our normal
447 * children self-reap, then this child was prevented by ptrace and we must
448 * reap it now, in that case we must also wake up sub-threads sleeping in
451 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
457 if (p->exit_state != EXIT_ZOMBIE)
460 dead = !thread_group_leader(p);
462 if (!dead && thread_group_empty(p)) {
463 if (!same_thread_group(p->real_parent, tracer))
464 dead = do_notify_parent(p, p->exit_signal);
465 else if (ignoring_children(tracer->sighand)) {
466 __wake_up_parent(p, tracer);
470 /* Mark it as in the process of being reaped. */
472 p->exit_state = EXIT_DEAD;
476 static int ptrace_detach(struct task_struct *child, unsigned int data)
478 if (!valid_signal(data))
481 /* Architecture-specific hardware disable .. */
482 ptrace_disable(child);
483 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
485 write_lock_irq(&tasklist_lock);
487 * We rely on ptrace_freeze_traced(). It can't be killed and
488 * untraced by another thread, it can't be a zombie.
490 WARN_ON(!child->ptrace || child->exit_state);
492 * tasklist_lock avoids the race with wait_task_stopped(), see
493 * the comment in ptrace_resume().
495 child->exit_code = data;
496 __ptrace_detach(current, child);
497 write_unlock_irq(&tasklist_lock);
499 proc_ptrace_connector(child, PTRACE_DETACH);
505 * Detach all tasks we were using ptrace on. Called with tasklist held
508 void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
510 struct task_struct *p, *n;
512 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
513 if (unlikely(p->ptrace & PT_EXITKILL))
514 send_sig_info(SIGKILL, SEND_SIG_FORCED, p);
516 if (__ptrace_detach(tracer, p))
517 list_add(&p->ptrace_entry, dead);
521 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
527 int this_len, retval;
529 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
530 retval = access_process_vm(tsk, src, buf, this_len, 0);
536 if (copy_to_user(dst, buf, retval))
546 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
552 int this_len, retval;
554 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
555 if (copy_from_user(buf, src, this_len))
557 retval = access_process_vm(tsk, dst, buf, this_len, 1);
571 static int ptrace_setoptions(struct task_struct *child, unsigned long data)
575 if (data & ~(unsigned long)PTRACE_O_MASK)
578 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
579 if (!config_enabled(CONFIG_CHECKPOINT_RESTORE) ||
580 !config_enabled(CONFIG_SECCOMP))
583 if (!capable(CAP_SYS_ADMIN))
586 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
587 current->ptrace & PT_SUSPEND_SECCOMP)
591 /* Avoid intermediate state when all opts are cleared */
592 flags = child->ptrace;
593 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
594 flags |= (data << PT_OPT_FLAG_SHIFT);
595 child->ptrace = flags;
600 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
605 if (lock_task_sighand(child, &flags)) {
607 if (likely(child->last_siginfo != NULL)) {
608 *info = *child->last_siginfo;
611 unlock_task_sighand(child, &flags);
616 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
621 if (lock_task_sighand(child, &flags)) {
623 if (likely(child->last_siginfo != NULL)) {
624 *child->last_siginfo = *info;
627 unlock_task_sighand(child, &flags);
632 static int ptrace_peek_siginfo(struct task_struct *child,
636 struct ptrace_peeksiginfo_args arg;
637 struct sigpending *pending;
641 ret = copy_from_user(&arg, (void __user *) addr,
642 sizeof(struct ptrace_peeksiginfo_args));
646 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
647 return -EINVAL; /* unknown flags */
652 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
653 pending = &child->signal->shared_pending;
655 pending = &child->pending;
657 for (i = 0; i < arg.nr; ) {
659 s32 off = arg.off + i;
661 spin_lock_irq(&child->sighand->siglock);
662 list_for_each_entry(q, &pending->list, list) {
664 copy_siginfo(&info, &q->info);
668 spin_unlock_irq(&child->sighand->siglock);
670 if (off >= 0) /* beyond the end of the list */
674 if (unlikely(is_compat_task())) {
675 compat_siginfo_t __user *uinfo = compat_ptr(data);
677 if (copy_siginfo_to_user32(uinfo, &info) ||
678 __put_user(info.si_code, &uinfo->si_code)) {
686 siginfo_t __user *uinfo = (siginfo_t __user *) data;
688 if (copy_siginfo_to_user(uinfo, &info) ||
689 __put_user(info.si_code, &uinfo->si_code)) {
695 data += sizeof(siginfo_t);
698 if (signal_pending(current))
710 #ifdef PTRACE_SINGLESTEP
711 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
713 #define is_singlestep(request) 0
716 #ifdef PTRACE_SINGLEBLOCK
717 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
719 #define is_singleblock(request) 0
723 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
725 #define is_sysemu_singlestep(request) 0
728 static int ptrace_resume(struct task_struct *child, long request,
733 if (!valid_signal(data))
736 if (request == PTRACE_SYSCALL)
737 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
739 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
741 #ifdef TIF_SYSCALL_EMU
742 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
743 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
745 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
748 if (is_singleblock(request)) {
749 if (unlikely(!arch_has_block_step()))
751 user_enable_block_step(child);
752 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
753 if (unlikely(!arch_has_single_step()))
755 user_enable_single_step(child);
757 user_disable_single_step(child);
761 * Change ->exit_code and ->state under siglock to avoid the race
762 * with wait_task_stopped() in between; a non-zero ->exit_code will
763 * wrongly look like another report from tracee.
765 * Note that we need siglock even if ->exit_code == data and/or this
766 * status was not reported yet, the new status must not be cleared by
767 * wait_task_stopped() after resume.
769 * If data == 0 we do not care if wait_task_stopped() reports the old
770 * status and clears the code too; this can't race with the tracee, it
771 * takes siglock after resume.
773 need_siglock = data && !thread_group_empty(current);
775 spin_lock_irq(&child->sighand->siglock);
776 child->exit_code = data;
777 wake_up_state(child, __TASK_TRACED);
779 spin_unlock_irq(&child->sighand->siglock);
784 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
786 static const struct user_regset *
787 find_regset(const struct user_regset_view *view, unsigned int type)
789 const struct user_regset *regset;
792 for (n = 0; n < view->n; ++n) {
793 regset = view->regsets + n;
794 if (regset->core_note_type == type)
801 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
804 const struct user_regset_view *view = task_user_regset_view(task);
805 const struct user_regset *regset = find_regset(view, type);
808 if (!regset || (kiov->iov_len % regset->size) != 0)
811 regset_no = regset - view->regsets;
812 kiov->iov_len = min(kiov->iov_len,
813 (__kernel_size_t) (regset->n * regset->size));
815 if (req == PTRACE_GETREGSET)
816 return copy_regset_to_user(task, view, regset_no, 0,
817 kiov->iov_len, kiov->iov_base);
819 return copy_regset_from_user(task, view, regset_no, 0,
820 kiov->iov_len, kiov->iov_base);
824 * This is declared in linux/regset.h and defined in machine-dependent
825 * code. We put the export here, near the primary machine-neutral use,
826 * to ensure no machine forgets it.
828 EXPORT_SYMBOL_GPL(task_user_regset_view);
831 int ptrace_request(struct task_struct *child, long request,
832 unsigned long addr, unsigned long data)
834 bool seized = child->ptrace & PT_SEIZED;
836 siginfo_t siginfo, *si;
837 void __user *datavp = (void __user *) data;
838 unsigned long __user *datalp = datavp;
842 case PTRACE_PEEKTEXT:
843 case PTRACE_PEEKDATA:
844 return generic_ptrace_peekdata(child, addr, data);
845 case PTRACE_POKETEXT:
846 case PTRACE_POKEDATA:
847 return generic_ptrace_pokedata(child, addr, data);
849 #ifdef PTRACE_OLDSETOPTIONS
850 case PTRACE_OLDSETOPTIONS:
852 case PTRACE_SETOPTIONS:
853 ret = ptrace_setoptions(child, data);
855 case PTRACE_GETEVENTMSG:
856 ret = put_user(child->ptrace_message, datalp);
859 case PTRACE_PEEKSIGINFO:
860 ret = ptrace_peek_siginfo(child, addr, data);
863 case PTRACE_GETSIGINFO:
864 ret = ptrace_getsiginfo(child, &siginfo);
866 ret = copy_siginfo_to_user(datavp, &siginfo);
869 case PTRACE_SETSIGINFO:
870 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
873 ret = ptrace_setsiginfo(child, &siginfo);
876 case PTRACE_GETSIGMASK:
877 if (addr != sizeof(sigset_t)) {
882 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t)))
889 case PTRACE_SETSIGMASK: {
892 if (addr != sizeof(sigset_t)) {
897 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
902 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
905 * Every thread does recalc_sigpending() after resume, so
906 * retarget_shared_pending() and recalc_sigpending() are not
909 spin_lock_irq(&child->sighand->siglock);
910 child->blocked = new_set;
911 spin_unlock_irq(&child->sighand->siglock);
917 case PTRACE_INTERRUPT:
919 * Stop tracee without any side-effect on signal or job
920 * control. At least one trap is guaranteed to happen
921 * after this request. If @child is already trapped, the
922 * current trap is not disturbed and another trap will
923 * happen after the current trap is ended with PTRACE_CONT.
925 * The actual trap might not be PTRACE_EVENT_STOP trap but
926 * the pending condition is cleared regardless.
928 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
932 * INTERRUPT doesn't disturb existing trap sans one
933 * exception. If ptracer issued LISTEN for the current
934 * STOP, this INTERRUPT should clear LISTEN and re-trap
937 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
938 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
940 unlock_task_sighand(child, &flags);
946 * Listen for events. Tracee must be in STOP. It's not
947 * resumed per-se but is not considered to be in TRACED by
948 * wait(2) or ptrace(2). If an async event (e.g. group
949 * stop state change) happens, tracee will enter STOP trap
950 * again. Alternatively, ptracer can issue INTERRUPT to
951 * finish listening and re-trap tracee into STOP.
953 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
956 si = child->last_siginfo;
957 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
958 child->jobctl |= JOBCTL_LISTENING;
960 * If NOTIFY is set, it means event happened between
961 * start of this trap and now. Trigger re-trap.
963 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
964 ptrace_signal_wake_up(child, true);
967 unlock_task_sighand(child, &flags);
970 case PTRACE_DETACH: /* detach a process that was attached. */
971 ret = ptrace_detach(child, data);
974 #ifdef CONFIG_BINFMT_ELF_FDPIC
975 case PTRACE_GETFDPIC: {
976 struct mm_struct *mm = get_task_mm(child);
977 unsigned long tmp = 0;
984 case PTRACE_GETFDPIC_EXEC:
985 tmp = mm->context.exec_fdpic_loadmap;
987 case PTRACE_GETFDPIC_INTERP:
988 tmp = mm->context.interp_fdpic_loadmap;
995 ret = put_user(tmp, datalp);
1000 #ifdef PTRACE_SINGLESTEP
1001 case PTRACE_SINGLESTEP:
1003 #ifdef PTRACE_SINGLEBLOCK
1004 case PTRACE_SINGLEBLOCK:
1006 #ifdef PTRACE_SYSEMU
1008 case PTRACE_SYSEMU_SINGLESTEP:
1010 case PTRACE_SYSCALL:
1012 return ptrace_resume(child, request, data);
1015 if (child->exit_state) /* already dead */
1017 return ptrace_resume(child, request, SIGKILL);
1019 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1020 case PTRACE_GETREGSET:
1021 case PTRACE_SETREGSET: {
1023 struct iovec __user *uiov = datavp;
1025 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1028 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1029 __get_user(kiov.iov_len, &uiov->iov_len))
1032 ret = ptrace_regset(child, request, addr, &kiov);
1034 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1039 case PTRACE_SECCOMP_GET_FILTER:
1040 ret = seccomp_get_filter(child, addr, datavp);
1050 static struct task_struct *ptrace_get_task_struct(pid_t pid)
1052 struct task_struct *child;
1055 child = find_task_by_vpid(pid);
1057 get_task_struct(child);
1061 return ERR_PTR(-ESRCH);
1065 #ifndef arch_ptrace_attach
1066 #define arch_ptrace_attach(child) do { } while (0)
1069 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1070 unsigned long, data)
1072 struct task_struct *child;
1075 if (request == PTRACE_TRACEME) {
1076 ret = ptrace_traceme();
1078 arch_ptrace_attach(current);
1082 child = ptrace_get_task_struct(pid);
1083 if (IS_ERR(child)) {
1084 ret = PTR_ERR(child);
1088 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1089 ret = ptrace_attach(child, request, addr, data);
1091 * Some architectures need to do book-keeping after
1095 arch_ptrace_attach(child);
1096 goto out_put_task_struct;
1099 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1100 request == PTRACE_INTERRUPT);
1102 goto out_put_task_struct;
1104 ret = arch_ptrace(child, request, addr, data);
1105 if (ret || request != PTRACE_DETACH)
1106 ptrace_unfreeze_traced(child);
1108 out_put_task_struct:
1109 put_task_struct(child);
1114 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1120 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
1121 if (copied != sizeof(tmp))
1123 return put_user(tmp, (unsigned long __user *)data);
1126 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1131 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
1132 return (copied == sizeof(data)) ? 0 : -EIO;
1135 #if defined CONFIG_COMPAT
1137 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1138 compat_ulong_t addr, compat_ulong_t data)
1140 compat_ulong_t __user *datap = compat_ptr(data);
1141 compat_ulong_t word;
1146 case PTRACE_PEEKTEXT:
1147 case PTRACE_PEEKDATA:
1148 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
1149 if (ret != sizeof(word))
1152 ret = put_user(word, datap);
1155 case PTRACE_POKETEXT:
1156 case PTRACE_POKEDATA:
1157 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
1158 ret = (ret != sizeof(data) ? -EIO : 0);
1161 case PTRACE_GETEVENTMSG:
1162 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1165 case PTRACE_GETSIGINFO:
1166 ret = ptrace_getsiginfo(child, &siginfo);
1168 ret = copy_siginfo_to_user32(
1169 (struct compat_siginfo __user *) datap,
1173 case PTRACE_SETSIGINFO:
1174 memset(&siginfo, 0, sizeof siginfo);
1175 if (copy_siginfo_from_user32(
1176 &siginfo, (struct compat_siginfo __user *) datap))
1179 ret = ptrace_setsiginfo(child, &siginfo);
1181 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1182 case PTRACE_GETREGSET:
1183 case PTRACE_SETREGSET:
1186 struct compat_iovec __user *uiov =
1187 (struct compat_iovec __user *) datap;
1191 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1194 if (__get_user(ptr, &uiov->iov_base) ||
1195 __get_user(len, &uiov->iov_len))
1198 kiov.iov_base = compat_ptr(ptr);
1201 ret = ptrace_regset(child, request, addr, &kiov);
1203 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1209 ret = ptrace_request(child, request, addr, data);
1215 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1216 compat_long_t, addr, compat_long_t, data)
1218 struct task_struct *child;
1221 if (request == PTRACE_TRACEME) {
1222 ret = ptrace_traceme();
1226 child = ptrace_get_task_struct(pid);
1227 if (IS_ERR(child)) {
1228 ret = PTR_ERR(child);
1232 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1233 ret = ptrace_attach(child, request, addr, data);
1235 * Some architectures need to do book-keeping after
1239 arch_ptrace_attach(child);
1240 goto out_put_task_struct;
1243 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1244 request == PTRACE_INTERRUPT);
1246 ret = compat_arch_ptrace(child, request, addr, data);
1247 if (ret || request != PTRACE_DETACH)
1248 ptrace_unfreeze_traced(child);
1251 out_put_task_struct:
1252 put_task_struct(child);
1256 #endif /* CONFIG_COMPAT */